LaTeBO5: a new borotellurite with a large birefringence activated by the highly distorted [Te(iv)O4] group

PbTeB4O9: a lead tellurium borate with unprecedented fundamental building block [B4O10] and large birefringence

Herein, the first lead tellurium borate, PbTeB4O9, with an unprecedented fundamental building block [B4O10] was successfully synthesized. The near-parallel alignment of [B4O10] groups and [TeO3] polyhedra resulted in a high birefringence (0.099@1064 nm). The structure-property relationship was discussed by using the first-principles calculations.

Rational Design of a Niobium Tellurite Crystal Nb2Te3O11 Exhibiting Good Overall Infrared NLO Performance by Structural Genetic Engineering

Nonlinear optical (NLO) materials have aroused increasing interest owing to their promising applications in optoelectronic technologies. Herein, we present the synthesis of an acentric niobium tellurite crystal, Nb2Te3O11, extracted via a spontaneous crystallization approach. It adopts a unique three-dimensional (3D) structure constructed by the distorted [TeO3], [TeO4], and [NbO6] fundamental building units. The title compound undergoes incongruent melting at approximately 807 °C. Optical characterizations demonstrate that Nb2Te3O11 possesses an extended transparency window beyond 5 μm, along with a large band gap value of 3.1 eV. Moreover, the as-synthesized Nb2Te3O11 displays an appreciable second-harmonic generation (SHG) response of 2 × KDP and a notable birefringence of 0.11 under 1064 nm for achieving phase-matching. In addition, theoretical calculation investigations suggest that the intriguing optical properties are ascribed to the cooperative effect of three types of NLO-active motifs: [TeO3] pyramids, [TeO4] seesaws, and [NbO6] octahedra. These attributes provide new functional insights into Nb2Te3O11 and enrich the family of NLO crystals in the mid-infrared region.

Sr3 [SnOSe3 ][CO3 ]: A Heteroanionic Nonlinear Optical Material Containing Planar π-conjugated [CO3 ] and Heteroleptic [SnOSe3 ] Anionic Groups

Inorganic heteroanionic materials are attracting increasing attention for exploring new nonlinear optical (NLO) materials because they could better satisfy the necessary but conflicting properties of NLO crystals, e.g. large SHG response and wide band-gap. Up to now, the reports on heteroanionic NLO materials have mainly focused on ultraviolet or visible oxide-based fluoroborates, fluorophosphates, borate-phosphates and borate-iodates. However, chalcogenides containing different kinds of anionic groups have barely been reported. Herein, we have synthesized the first oxychalcogenide-carbonate, Sr₃ [SnOSe₃ ][CO₃ ] that contains two different kinds of anionic groups, [SnOSe₃ ] and [CO₃ ]. It crystallizes in a noncentrosymmetric space group and exhibits fascinating NLO properties, including a large SHG response (≈1×AGS), sufficient birefringence (0.12 @1064 nm), wide band-gap (3.46 eV) and high laser damage threshold (240 MW cm^-2 ). These make Sr₃ [SnOSe₃ ][CO₃ ] a promising NLO crystal.